The fact that KNX was and still is the standard of choice for high-performance building automation is also due to its comprehensive range of applications. It can be used to bring together different systems such as installation technology, heating, ventilation and air conditioning, security, household appliances and audio/video applications. At the same time, networking via IP technology enables further applications.

The actual installation is relatively simple and can be carried out in various ways. KNX is usually wired in a line structure. A free tree structure results from any number of branches. Twisted pair cables, i.e. 2-wire control cables, are laid for this purpose. The KNX bus also supplies the devices with 29 volts DC.

In the KNX system, the power network and the control network are separated from each other. A control device, the actuator, is connected between consumers such as heating controls, lamps and window openers. This is connected to the KNX bus and receives serially transmitted data packets, known as telegrams. If such a telegram contains the command to supply voltage to the consumer, it switches the mains voltage through to the device via a relay. One possible supplier of telegrams is sensors. These can take over control in the KNX system themselves and, for example, switch an actuator on the heating or blinds at a certain temperature or brightness value. On the other hand, a computer can act as a central interface to send the telegrams. For example, after various sensor information has reached it or as part of a pre-programmed time switch.

Building management solutions are used in many current KNX systems. Products such as 'U.motion' enable the connection of KNX functions, door communication, IP cameras, VoIP telephones and many other solutions. These are controlled via touch panels, which are available in various sizes, from 7-inch to 15-inch devices. Depending on the scope of the KNX installation, different server variants can be selected.

Convenient operation via app

Such a system also demonstrates its advantages through integration with other bus systems as well as with smartphones and tablets. These become the control center via apps and enable complete control of the building. Door communication is also possible, for example in conjunction with Ritto door stations. In many areas, this brings great convenience, for example when door calls can be answered from the comfort of your sofa. It is also possible for many functions to be triggered by smartphones and similar devices. For example, the heating can be controlled fully automatically as soon as one of the residents leaves home. Given these if-then scenarios, the range of possibilities is almost endless.

Building management via smartphone, tablet and touch panel.

© Mertens

KNX installation is not cut off from technical developments. Ten years ago, no one would have thought that it would one day be possible to monitor the door intercom system from your vacation destination. However, the KNX standard has proven to be so future-proof and expandable that it can easily be upgraded to the current standard. This means that residents can set the optimum lighting mood at any time using a smartphone or tablet PC and the blinds allow more or less light into the rooms.

The app is also a useful helper when it comes to room temperature. The right number of degrees can be set in no time at all. Each room can be controlled individually. The software also offers added convenience and security: if, for example, the light in the garage is still on even though no one is at home, the status can be checked directly via the app and changed if necessary. Such apps also help to save energy: Thanks to the intelligent visualization of the measured values, consumption figures can be called up conveniently. Individual rooms or areas can be named and addressed with defined functions. Customized configurations for different users are also conceivable.

Shaping the energy transition with KNX

Logic controllers such as "homeLYnk" link energy consumers, storage systems and power generators with each other.

© Merten

Consistently taken further, the KNX standard can be used not only for personal living comfort, but also as part of a comprehensive smart home approach. KNX can be part of an intelligent automation system that is able to control and manage both the energy produced and consumed in the home. Based on logic controllers, it creates a connection between energy consumers, storage systems, power generators such as photovoltaic systems, energy management and electromobility and can integrate all these elements into smart grids. It therefore also supports the energy transition by exchanging energy data with the grid operators. The interaction works smoothly, as an example of a daily routine can illustrate. While the residents of the house prepare for their day in the morning, the logic controller charges the empty battery as the sun rises. The system systematically directs surplus energy to non-flexible consumers - so the washing machine or electric car still have to run on empty. The vehicle can be charged as soon as the sun, and therefore the energy production, is at its zenith. In the meantime, the photovoltaic system feeds energy into the grid, provided there is still residual energy available.

The electric car is now fully charged. The washing machine can now be filled and is waiting for the signal to start. However, as the sun is no longer shining, the photovoltaic system is no longer generating electricity. However, as the battery is fully charged thanks to the surplus energy at midday, the wash cycle can still begin. Finally, the stationary battery is fully discharged overnight by various consumers. From now on, it is supplied by the grid. The non-flexible loads are supplied in any case. The flexible loads are left out and are only switched on if this is expressly desired. Ultimately, of course, the user is not bound to such a scenario. Depending on the daily routine and the system, they can have the control system adapted to suit their needs.

KNX should be part of every intelligent building in the future. The technology is anything but cost-intensive and modern solutions increase convenience with their many functions. Last but not least, KNX helps to keep a transparent eye on energy costs.